CVE-2019-9323 in Android
Summary
by MITRE
In the Wallpaper Manager service, there is a possible information disclosure due to a missing permission check. Any application can access wallpaper image with no additional execution privileges needed. User interaction is not needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-30770233
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Analysis
by VulDB Data Team • 09/12/2020
The vulnerability identified as CVE-2019-9323 resides within the Wallpaper Manager service component of Android operating systems, specifically affecting Android 10 and earlier versions. This represents a critical security flaw that undermines the platform's permission model and data protection mechanisms. The issue manifests as an information disclosure vulnerability where sensitive wallpaper image data becomes accessible to any application running on the device without requiring additional privileges or user interaction. This weakness directly violates fundamental security principles that govern access control and data confidentiality in mobile operating systems.
The technical flaw stems from a missing permission check within the Wallpaper Manager service implementation. When applications attempt to access wallpaper images through the service interface, the system fails to validate whether the requesting application possesses the appropriate permissions to access such sensitive data. This missing validation creates an unauthorized access path that allows any application to retrieve wallpaper images regardless of its security context or intended functionality. The vulnerability operates at the system service level, where proper access controls should enforce strict permission boundaries between different applications and system components. According to CWE classification, this maps to CWE-284: Improper Access Control, which specifically addresses insufficient access control mechanisms that allow unauthorized access to resources.
The operational impact of this vulnerability extends beyond simple information disclosure, as wallpaper images may contain sensitive metadata or visual information that could be exploited for social engineering attacks, user profiling, or targeted phishing campaigns. Attackers can leverage this vulnerability to gather visual intelligence about device users, potentially identifying personal preferences, recent activities, or even sensitive visual elements that might be used in sophisticated social engineering attacks. The lack of user interaction requirement for exploitation makes this vulnerability particularly dangerous as it can be triggered automatically without any user awareness or consent. This aligns with ATT&CK technique T1566: Phishing for Information, where adversaries can collect visual intelligence to support their operations. The vulnerability affects the Android platform's core security model by undermining the principle of least privilege, where applications should only have access to resources necessary for their operation.
Mitigation strategies for this vulnerability require immediate system updates and patches from device manufacturers and Google. The recommended approach involves implementing proper permission checks within the Wallpaper Manager service to ensure that only authorized applications can access wallpaper image data. This includes validating application signatures, enforcing proper access control lists, and implementing mandatory access controls that prevent unauthorized data access. Device manufacturers should prioritize rolling out security patches to affected Android versions and ensure proper testing of permission mechanisms. Additionally, security teams should implement monitoring solutions to detect unauthorized access attempts to wallpaper data and establish proper incident response procedures. The vulnerability highlights the critical importance of comprehensive security testing for system services and the need for regular security audits to identify missing access control mechanisms. Organizations should also consider implementing application whitelisting policies and enhanced monitoring of system service access patterns to prevent exploitation of similar vulnerabilities.